And once again, Unarmed Strikes can heal if you're weak enough:
Damage. You make an attack roll against the target. Your bonus to hit equals your Strength modifier + your Proficiency Bonus. On a hit, the target takes Bludgeoning damage equal to 1 + your Strength modifier.
Dextrous Attacks. You can use Dexterity instead of Strength for the attack and damage rolls of your Unarmed Strikes and Monk Weapons. In addition, when you choose the Grapple or Shove option, you can use your Dexterity modifier instead of Strength to determine the saving throw DC.
I don't see what that has to do with the omission of the "minimum 0" (or 1) from the general description of unarmed strikes that hypothetically could mean doing negative damage.
As new general rules on damage rolls do not appear in the document, the rules on p.196 of the 2014 PHB would still apply, which is where 5e specifies that you can't deal negative damage (be it with an attack, spell, or any other damage dealing mechanic).
Thanks! I don't have my PHB on me (traveling for the holidays), but I was pretty certain that DnD had a "0 damage is not damage" and "negative damage is treated as 0" sort of rule, similar to Magic.